Chemical-Demulsifier Development Based on Critical-Electric-Field Measurements

Abstract

Summary Resolution of water-and-oil emulsions is critical to the oilfield industry. A wide variety of undesirable emulsions are formed during the production, handling, and processing of crude oil. Although various methods are used, dehydration of crude oils is achieved mostly by gravitational sedimentation, normally at elevated temperatures and with the addition of chemical demulsifiers. The quantitative evaluation of emulsion stability by a critical-electric-field (CEF) technique was developed to play a significant role in chemical-demulsifier research. It was found that the CEF technique is useful not only in the evaluation of water-in-oil-emulsion stability, but also in studying the mechanisms of stabilization and demulsification. A method was developed to study the mechanism of emulsion stabilization in terms of flocculation and coalescence behavior of a crude-oil emulsion. The effect of chemical demulsifiers on emulsion stability was evaluated in terms of the method developed in this study. By following this approach, it is possible to determine the relative amount of energy required for both flocculation and coalescence in the presence of a chemical demulsifier.